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Concurrent EEG and Functional MRI Recording and Integration Analysis for Dynamic Cortical Activity Imaging
Published on: June 30, 2018
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A simultaneous EEG-fMRI study of thalamic load-dependent working memory delay period activity
Bernard A Gomes1, Chelsea Reichert Plaska2, Jefferson Ortega3
1Program in Cognitive Neuroscience, The Graduate Center of the City University of New York, New York, NY, United States.
Frontiers in Behavioral Neuroscience
|March 13, 2023
Summary
The thalamus plays a role in working memory (WM) by filtering sensory information. Higher thalamic activity during low-load WM suggests it prioritizes fewer stimuli when distractions are present.
Area of Science:
- Neuroscience
- Cognitive Psychology
Background:
- Working memory (WM) is crucial for executive functions, involving information maintenance during stimulus encoding and retrieval.
- Prefrontal and parietal cortex roles in WM are well-documented, but subcortical contributions, particularly the thalamus, require further investigation in humans.
Purpose of the Study:
- To investigate the thalamus's role during the working memory (WM) delay period using simultaneous electroencephalogram (EEG)-functional magnetic resonance imaging (fMRI).
- To examine how memory load affects thalamic activity during WM maintenance.
Main Methods:
- Employed a modified Sternberg paradigm with simultaneous EEG-fMRI.
- Participants encoded naturalistic scenes under low and high memory load conditions.
- During the delay period, participants viewed scrambled scenes as a perceptual baseline.
Main Results:
- Thalamic activation during the WM delay period showed load-dependent effects.
- Higher EEG source amplitudes were observed in the bilateral thalamus during the low-load condition compared to the high-load condition (160-390 ms post-delay onset).
Conclusions:
- Thalamic activation patterns suggest a capacity-limited sensory filtering role in working memory (WM).
- Elevated thalamic activity in the low-load condition indicates a function in prioritizing fewer stimuli amidst interfering perceptual input during WM consolidation.
- Findings contribute to understanding the thalamus's involvement in sensory gating within WM.
